They are showing up - just down the bottom of the page. My guess would be that one of the elements in you widgets is too large for the widget column. You need to either:
1. Reduce the size of the elements; or
2. Increase the space available.
If you are going to do (1), then you need to look at the platial and the flickr ones, as they are too wide. I think this cannot be done, so change theme to one with only one sidebar and that should work.